Entity

Time filter

Source Type

Pingdingshan, China

Lin B.,China University of Mining and Technology | Zhang J.,China University of Mining and Technology | Zhang J.,Zhongping Energy Chemical Group | Shen C.,China University of Mining and Technology | And 2 more authors.
International Journal of Mining Science and Technology | Year: 2012

Difficulties with soft coal seams having a high gas content and high stress levels can be addressed by a technology of pressure relief and permeability increase. Slotting the seam by auxiliary drilling with a water jet that breaks the coal and slots the coal seam during the process of retreat drilling achieves pressure relief and permeability increase. Improved efficiency of gas extraction from a field test, high gas coal seam was observed. Investigating the theory of pressure relief and permeability increase required analyzing the characteristics of the double power slotting process and the effects of coal pressure relief and permeability increase. The influence of confining pressure on coal physical properties was examined by using FLAC3D software code to simulate changes of coal stress within the tool destruction area. The double power joint drilling method was modeled. Field experiments were performed and the effects are analyzed. This research shows that there is an "islanding effect" in front of the joint double power drill and slotting equipment. The failure strength of the coal seam is substantially reduced within the tool destruction area. Drilling depths are increased by 72% and the diameter of the borehole is increased by 30%. The amount of powdered coal extracted from the drill head increases by 17 times when using the new method. A 30 day total flow measurement from the double power drilled and slotted bores showed that gas extraction increased by 1.3 times compared to the standard drilled bores. Gas concentrations increased from 30% to 60% and were more stable so the overall extraction efficiency increased by a factor of two times. © 2012 Published by Elsevier B.V. on behalf of China University of Mining and Technology. Source


Zhai C.,China University of Mining and Technology | Li M.,China University of Mining and Technology | Sun C.,China University of Mining and Technology | Zhang J.,Zhongping Energy Chemical Group | And 2 more authors.
International Journal of Mining Science and Technology | Year: 2012

Aiming at the uncontrollable problem of extension direction of coal seam hydraulic fracturing, this study analyzed the course of fractures variation around the boreholes in process of hydraulic fracturing, and carried out the numerical simulations to investigate the effect of artificial predetermined fractures on stress distribution around fractured holes. The simulation results show that partial coal mass occurs relatively strong shear failure and forms weak surfaces, and then fractures extended along the desired direction while predetermined fractures changed stress distribution. Directional fracturing makes the fractures link up and the pressure on coal mass is relieved within fractured regions. Combining deep hole controlling blasting with hydraulic fracturing was proposed to realize the extension guiding-controlling technology of coal seam fractures. Industrial experiments prove that this technology can avoid local stress concentration and dramatically widen the pressure relief scope of deep hole controlling blasting. The permeability of fractured coal seam increased significantly, and gas extraction was greatly improved. Besides, regional pressure relief and permeability increase was achieved in this study. © 2012 Published by Elsevier B.V. on behalf of China University of Mining and Technology. Source


Gao M.-S.,China University of Mining and Technology | Gao M.-S.,Yongcheng Coal and Electricity Holding Group Co. | Guo C.-S.,Zhongping Energy Chemical Group | Li J.-F.,China University of Mining and Technology | And 2 more authors.
Zhongguo Kuangye Daxue Xuebao/Journal of China University of Mining and Technology | Year: 2011

Stabilizing the load bearing structure of a roadway roof when it consists of a thick, soft layer can not be done with a set of equal-length anchors. This is because the roof will separate and deformation will destroy the structure. A multi-length support method is proposed. The lower roof is supported with bolts that form a shell. Then a second set of middle length anchors are installed into the roof that make a second load bearing structure. Thirdly, the long anchors are installed deeply into the roof that form a compositing bolted bearing structure. Thus, the thick soft layer of the roof is controlled by this multi-step, three dimensional support structure because of the load bearing strength and thickness it creates. A theoretical analysis of the support is presented. A successful application of the technology in the 11151 gateway of the Guqiao mine is described. The separation of the lower roof of roadway was about 10 and 14 millimeters, and the maximum separation in the deep roof was about 23 millimeters. Source


Zhou H.,Henan University of Urban Construction | Liu P.,Henan University of Urban Construction | Wang Z.,Zhongping Energy Chemical Group
Advanced Materials Research | Year: 2011

The modification of sodium trititanate whisker surface was performed by means of impregnation procedure to fabricate the modified sodium trititanate whisker, which was characterized by infrared spectroscopy(IR). Its adsorptive performance for Cd(II) in a static system was investigated by inductively coupled plasma atomic emission spectrometry(FAAS). The main factors affecting adsorption and desorption of Cd(II), the adsorptive capacity of Cd(II) in optimal condition and adsorption isotherm and the influence of coexistent ions were examined. The adsorptive rate for Cd(II) on 0.2500 g of modified sodium trititanate whisker at PH 5.0 was the best. Cd(II) adsorbed on the modified sodium tretitanate whisker could be eluted with 10 mL of 2.0 mol/L HCl. The adsorptive performance of modified sodium trititanate whisker was better than that of unmodified sodium trititanate whisker. © 2011 Trans Tech Publications, Switzerland. Source


Zhang J.-G.,China University of Mining and Technology | Zhang J.-G.,Zhongping Energy Chemical Group | Lin B.-Q.,China University of Mining and Technology | Zhai C.,China University of Mining and Technology
Caikuang yu Anquan Gongcheng Xuebao/Journal of Mining and Safety Engineering | Year: 2012

In this paper, in order to resolve the problem of gas and coal outburst in the drilling process of coal seam with high concentration of gas and low permeability, the gas-outburst prevention technology of high pressure hydraulic-cutting seam through layer was developed, which is integrated by drilling and seam cutting. Numerical simulation method was used to compare the pressure relief effects of borehole drilling and high pressure hydraulic-cutting seam. The results show that the pressure relief effect of high pressure hydraulic-cutting seam is much better than that of seam drilling. The cutting slit has broken the "bottleneck effect" around the drilling hole, and the extension of fractures and weak planes in coal mass is transformed into interlaced transfixion fracture network, which increases the permeability of coal mass and promotes the gas release. Industrial experiments indicate that compared with general method of coal seam drilling, the high pressure hydraulic-cutting seam through layer produces a better effect of pressure relieving and permeability improving, while the flow of drilling gas extraction and disturbance volume of coal mass have increased substantially, which improves the gas extraction efficiency. Source

Discover hidden collaborations